Unraveling a crosstalk regulatory network of temporal aroma accumulation in tea plant (Camellia sinensis) leaves by integration of metabolomics and transcriptomics

et al. 2019

Front. Plant Sci.

Oolong tea is a popular and semi-fermented beverage. During the processing of tea leaves, withering is the first indispensable process for improving flavor. However, the roles of long non-coding RNAs (lncRNAs) and the characteristic secondary metabolites during the withering of oolong tea leaves remain unknown. In this study, phytochemical analyses indicated that total polyphenols, flavonoids, catechins, epigallocatechin (EGC), catechin gallate (CG), gallocatechin gallate (GCG), epicatechin gallate (ECG), and epigallocatechin gallate (EGCG) were all less abundant in the solar-withered leaves (SW) than in the fresh leaves (FL) and indoor-withered leaves (IW). In contrast, terpenoid, jasmonic acid (JA), and methyl jasmonate (MeJA) contents were higher in the SW than in the FL and IW. By analyzing the transcriptome data, we detected 32,036 lncRNAs. On the basis of the Kyoto Encyclopedia of Genes and Genomes analysis, the flavonoid metabolic pathway, the terpenoid metabolic pathway, and the JA/MeJA biosynthesis and signal transduction pathway were enriched pathways. Additionally, 63 differentially expressed lncRNAs (DE-lncRNAs) and 23 target genes were identified related to the three pathways. A comparison of the expression profiles of the DE-lncRNAs and their target genes between the SW and IW revealed four up-regulated genes (FLS, CCR, CAD, and HCT), seven up-regulated lncRNAs, four down-regulated genes (4CL, CHI, F3H, and F3'H), and three downregulated lncRNAs related to flavonoid metabolism; nine up-regulated genes (DXS, CMK, HDS, HDR, AACT, MVK, PMK, GGPPS, and TPS), three up-regulated lncRNAs, and six down-regulated lncRNAs related to terpenoid metabolism; as well as six upregulated genes (LOX, AOS, AOC, OPR, ACX, and MFP2), four up-regulated lncRNAs, and three down-regulated lncRNAs related to JA/MeJA biosynthesis and signal transduction. These results suggested that the expression of DE-lncRNAs and their targets involved in the three pathways may be related to the low abundance of the total polyphenols, flavonoids, and catechins (EGC, CG, GCG, ECG, and EGCG) and the

Section: High Jasmonic Acid and Methyl Jasmonate Contents And An Endomentioning

confidence: 91%

Section: High Jasmonic Acid and Methyl Jasmonate Contents And An Endomentioning

confidence: 99%

Transcriptome and Phytochemical Analyses Provide New Insights Into Long Non-Coding RNAs Modulating Characteristic Secondary Metabolites of Oolong Tea (Camellia sinensis) in Solar-Withering

Zhu

et al. 2019

Front. Plant Sci.

“…Solar light, high contents of JA and MeJA, and eTMs regulatory mechanism are benefit to the accumulation of terpenoid in solar-withered leaves Light is a major environmental factor affecting the accumulation of terpenoid metabolites, and expression patterns of numerous genes involved in terpenoid metabolic pathway are regulated by light [112][113][114]. On the basis of previous research [115][116][117][118], light has a positive effect on the transcript levels of DXS, CMK, HDS, and HDR genes. In present study, the transcript levels of DXS, CMK, HDS, and HDR were significantly increased in SW than that in IW.…”

Section: Discussionmentioning

confidence: 96%

Transcriptome and phytochemical analyses provide new insights into long non-coding RNAs and characteristic secondary metabolites of oolong tea (Camellia sinensis) in solar-withering

Zhu

et al. 2019

Preprint

Background Oolong tea, a semi-fermented tea, was deeply loved by consumers. Among tea processing, withering is the first indispensable process for improving the unique flavor. However, the roles of long non-coding RNAs (lncRNAs) and characteristic secondary metabolites in withering of oolong tea remain unknown. Results Using phytochemical analyses, the total flavonoid, total catechins, EGC, CG, GCG, ECG, and EGCG were all present at significantly lower levels in solar-withered leaves (SW) than in fresh leaves (FL) and indoor-withered leaves (IW). However, terpenoid, JA, and MeJA were present at a higher level in SW than FL and IW. By analyzing the transcriptome data, we obtained a total of 32,036 lncRNAs. On the basis of Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, flavonoid metabolic pathway, terpenoid metabolic pathway, and JA/MeJA biosynthesis and signal transduction pathway were the representative pathways in this study. And a total of 63 differentially expressed-lncRNAs (DE-lncRNAs) and 23 target genes were identified in the 3 pathways. Analysis of the expression profiles of DE-lncRNAs and their target genes in SW compared with IW, we found that 4 up-regulated genes (FLS, CCR, CAD, and HCT), 7 up-regulated lncRNAs, 4 down-regulated genes (4CL, CHI, F3H, and F3'H), and 3 down-regulated lncRNAs in flavonoid metabolism; 9 up-regulated genes (DXS, CMK, HDS, HDR, AACT, MVK, PMK, GGPPS, and TPS), 3 up-regulated lncRNAs, 6 down-regulated lncRNAs in terpenoid metabolism; 6 up-regulated genes (LOX, AOS, AOC, OPR, ACX, and MFP2), 4 up-regulated lncRNAs, and 3 down-regulated lncRNAs in JA/MeJA biosynthesis and signal transduction pathway. Conclusions These results suggested that the expression of DE-lncRNAs and their targets involved in the 3 pathways maybe related to the low content of total flavonoid, total catechins, EGC, CG, GCG, ECG, and EGCG, and high content of terpenoid in SW. Moreover, solar light, high content of JA and MeJA, and the endogenous target mimics (eTMs) regulatory mechanism in SW were also crucial factors in increasing the terpenoid. These findings provide new insights into the view of "Kàn qīng shài qīng" that the solar-withering is more contribute to the high quality flavor of oolong tea compared to the indoor-withering.

“…Then, an array of TPS catalyzes FPP and GPP to generate kinds of terpenoids. Taken all together, 29 genes were annotated as TPSs, including CIN/LIC, MYS/OCS, LIS/NES, NUDX, FAS, CPS/HUS, SQS and BAS, and among them, nerolidol synthase (CsNES) [17], β-ocimene synthase (CsOCS) [18] and linalool synthase (CsLIS) [19] were recently functionally characterized in C. sinensis plants.…”

Section: Integration Of Gene Expression Levels and Terpenoid Profilesmentioning

confidence: 99%

“…Terpene synthases (TPSs) in plants are extensively studied and have been divided into seven subfamilies. The biosynthesis of terpenoids in Camellia sinensis is predicted based on the knowledge of the pathways elucidated in other plants, whereas the scenarios of genes to metabolites of terpenes biosynthesis pathway in tea plants remain uninvestigated and most of the TPSs in tea plants, until now, are unknown, except the recently characterized TPSs involved in the formation of (E)-nerolidol, linalool [17,18], ocimene [19] and α-farnesene [20].…”

mentioning

confidence: 99%

Scenarios of Genes-to-Terpenoids Network Led to the Identification of a Novel α/β-Farnesene/β-Ocimene Synthase in Camellia sinensis

Jianhui

Zhao

et al. 2020

IJMS

Terpenoids play vital roles in tea aroma quality and plants defense performance determination, whereas the scenarios of genes to metabolites of terpenes pathway remain uninvestigated in tea plants. Here, we report the use of an integrated approach combining metabolites, target gene transcripts and function analyses to reveal a gene-to-terpene network in tea plants. Forty-one terpenes including 26 monoterpenes, 14 sesquiterpenes and one triterpene were detected and 82 terpenes related genes were identified from five tissues of tea plants. Pearson correlation analysis resulted in genes to metabolites network. One terpene synthases whose expression positively correlated with farnesene were selected and its function was confirmed involved in the biosynthesis of α-farnesene, β-ocimene and β-farnesene, a very important and conserved alarm pheromone in response to aphids by both in vitro enzymatic assay in planta function analysis. In summary, we provided the first reliable gene-to-terpene network for novel genes discovery.